Underwater photography usually requires artificial lighting to overcome the low level of available natural light. The fluid environment makes fixed light support tripods and the like not a practical solution. Hence, the industry has developed various types of adjustable light support arms that extend out from the camera and locate lights, usually called strobes in the camera arts, at fixed desired positions relative to the camera. These so called strobe arms must be strong, rigid, and light weight. At the same time, they must be easily adjustable to different positions by a diver working underwater in difficult conditions. Still further, the strobe arms can not be too bulky or they will be very hard to move through the water. All of these conflicting requirements have not been well met by the simple aluminum tube arms generally utilized in the prior art. The present invention offers a much improved design.